1. Field of the Invention
The invention of the present application relates to an improved diagnostic test kit container structure and arrangement which facilitates conduct of diagnostic procedures, particularly by untrained persons. More specifically, the kit structure and arrangement facilitates performance of the diagnostic procedures for which the kit is designed by untrained consumers in the privacy of their own homes. The kit structure and arrangement is of particular value in connection with multi-step immunoassay procedures such as are involved, for example, in the detection of strep throat.
2. Description of the Prior Art
Recently the development of highly sensitive and specific diagnostic procedures has proceeded at a rapid pace. In fields such as clinical medicine, forensic sciences, environmental quality testing, food quality assurance, drug testing and other related areas, it has become possible through use of procedures based on immunochemical reactions to determine the presence and/or amount of trace substances in test samples even when such substances are present in very low concentrations in the order of parts per million, or even less. The development of non-radioactive labels or markers, such as gold sol particles and enzyme color formers, has facilitated the use of immunoassay diagnostic procedures outside of laboratory settings and in remote sites such as physician's offices and even the homes of the users. In the physician's office, immunological procedures are useful to provide rapid, simple assays which may be performed while the patient is still in the office so that the diagnosis can be accomplished without delay and treatment instituted during a single visit. Without such simple assays, it has often been necessary for the physician to collect a sample from the patient during a first visit and to have the sample analyzed by a clinical laboratory with the results reported back to the physician by the laboratory at a later time. In the meanwhile, the patient was sent home and was required to return for a second visit with the physician in order to receive appropriate treatment and/or medication. Manifestly, such delay was inefficient and inappropriate and in some cases could even be life threatening.
Simplified testing has also become desirable to facilitate testing by the consumer in the privacy of his or her own home. The results of such testing might, for example, indicate the necessity or lack of necessity of a visit to the physician. Examples of useful tests for the "at home" market include tests for pregnancy, ovulation, streptococcus infections such as strep throat, and other infections which are detectable by analysis of urine, saliva or other appropriate test samples.
For remote site testing, assuming appropriate sensitivity and specificity can be achieved, there are at least three other requirements for practical assay procedures. The first of these desirable factors is speed in that the assay must be performed in an acceptably short period of time, the shorter the better. Stability is also a desirable feature in that the components of the assay should be stable for an extended period of time without refrigeration or special handling. Finally, from a commercial view point it is desirable that the test be as simple as possible requiring only minimal or no instrumentation and precluding mistakes and poor performance resulting in incorrect interpretations.
Immunoassay kits employing enzyme markers are presently commercially available for determining conditions such as pregnancy and ovulation in the physician's office and in the home of the user. The technical components generally required in such kits are (1) a solid phase bearing immobilized antibody, (2) an enzyme labelled antibody, (3) a rinse solution (in some cases this may be the users tap water), and (4) a substrate for the enzyme. A typical procedure is that the sample is mixed with a solid phase and incubated (with or without a subsequent rinse step) and then the sample is discarded, the solid phase is then contacted with the enzyme labelled antibody and incubated. Alternatively, the sample and labelled antibody may be mixed first and the mixture brought into contact with the solid phase. In either case, the solid phase may then be rinsed and contacted by the substrate for the enzyme system. After a period of time (ca 5 minutes) the color of the solid phase is observed. One such assay is described in U.S. Letters Pat. No. 4,632,901. In other known kits based on immunological reactions, gold sol particles are used as markers or labels. The gold sol particles are capable of imparting color to the reaction product without the need for a substrate.
Detection of diseases such as strep throat is more difficult because the sample generally must be collected using a swab or the like and then the antigen in the sample must be prepared for immunoassay by using an extraction procedure to free it from its chemical matrix and/or expose the reactive determinants. To this end, the sample collected on the swab may be transported and introduced into a liquid extraction medium using the swab as a stirring implement. The antigen is then contained in a liquid milieu which may be brought into contact with the immunochemical components of the test procedure.
One of the difficulties encountered in the development of test devices and kits for remote site testing is the provision of practical pre-packaged disposable kits and devices to facilitate efficient, relatively inexpensive test procedures. This, of course, requires devices and kits which are inexpensive to construct, which have a shelf life appropriate to commercial usage, which are protected against contamination during handling, and which may be simply and readily utilized when the appropriate time arises. Use in the home, in particular, also requires explicit instructions which are easy to follow and leave essentially no room for error.
A number of prior test kit structures and arrangements are illustrated in U.S. Letters Pat. Nos. 3,203,540; 3,727,391; 3,743,088; and 3,917,456. However, these kits are of limited application and do not lend themselves to home testing situations.